Brake



May 9, 1944. P. M. FREER l 2,348,534

' 4 BRAKE' Filed Mayi,` 1943 2 Sheets-Sheet 1 INVENTOR.4

PHELPS M.FREER ATTQRNEYS 4 P. `M. rFREER May 9, 1944.

'BRAKE Filed May 3, 194s 2 Sheets-Sheet 2 O [VITI] JNVENToR. PHELPs M. FREER ATTORNEYS Patented May 9, 1944 uNiTED s'rA'nas PATENT OFFICE The invention relates to brakes and refers more particularly to brakes of that type having a brake drum and internal brake shoes movable against the drum by means having an axially movable central portion and a radially movable outer portion.

The invention has for an object to provide an improved brake of the above mentioned type having actuating mechanism for exerting a powerful force positioned with respect to the backing plate of the brake so that the backing plate may easily carry the stress to which it is subject by the actuating mechanism.

The invention has for another object to provide an improved actuating mechanism having a member whichris compelled to move axially upon its rotation.

The invention has for a further object to provide an improved actuating mechanism in which the rotatable member and the backing plate are provided with cooperating cam means for axiallyrnoving the rotatable member upon its rotation.

With these and other objects in view, the invention resides in the novel features of construction and combinations and arrangements of parts as more fully hereinafter set forth.

In the drawings:

Figure 1 is an elevation, with parts broken away and in section, of a brake embodying the invention; l

Figures 2, 3, 4, and 6 are cross sectionson the lines 2 2, 3 3, 4 4, 5 5, and 6 5, respectively, of Figure 1;

Figure '7 is a cross section on the line I 'l of Figure 6.

u The rotatable friction element of the brake is formed of thebrake drumV I having the internal annular friction face 2. The brakeA drum, as shown, is mounted upon the xed flange 3 of the hub 4, the xed iiange being provided with suitable means for securing a vehicle wheel thereto.

The non-rotatable friction element of the brake is formed of the lower, upper right and upper left brake shoes 5, 6 and l, respectively, and the resilient disc 8 upon the periphery of which the shoes are mounted. The disc has the central portion Sand the spokes IB radiating from the central portion and equally spaced from each other, there being one spoke for each shoe. The shoes are preferably T-section shoes having their webs u I-I formed at their outboard sides with the arcuate shoulders I2 for tting theradially outer ends of the backing plate I3 which is fixed either upon the axle housing or the steering spindle of the vehicle by suitable means, such as the upper and lower pairs of bolts I4 and I5, respectively. I5 are coil springs between theadjacent ends of the shoes for resiliently holding the shoes on the radially outer ends of the disc spokes. As shown, the webs II of the shoes are formed with the bayonet-shaped openings I'I for receiving the hooked ends of the coil springs.

The shoes 5, 6 and 1 are individually anchored and the anchoring arrangement is such that the non-rotatable element comprising the shoes and the disc may be adjustably centered relative to' the rotatable element comprising the` brakedrum.

The anchor for the upper right shoe 6 comprises.

the stud IB xedly secured to the backing plate I3 as by being riveted thereto and `having the integral polygonal head I9 extending through the radial slot 2|) in the plate 2l which isxedly secured to the inboard side of the web Il of the i upper right shoe and extends beyond the end the spokes I. The disc is dished toward the webs ofthe shoes and serves to retain the'wehs against thereof. The radial slot 20 has parallel sides and is of a length to provide for the necessary radial movement of the plate to permit the upper right shoe to engage and clear the brake drum. It will be noted that with the brake drum normally rotating in the direction of the arrow shown in Figure 1 the anchor for the upper right shoe is at the trailing end thereof. The anchors for the lower and upper left shoes 5 and 1, respectively,`

are located at their trailing ends with the brakeA drum rotating in the direction of the arrow in Figure 1. These anchors are alike and are located in the same horizontal plane. Furthermore, these anchors are adjustable and serve to center the non-rotatable element, comprisingvthe shoes and the disc, relative to the rotatable element, comprising the brake drum. In detail, the trailing end of each of the shoes 5 and 1 has secured to the inboard side of its web Il the plate 22 as by welding. The plate extends peripherally beyond the shoe and is provided with the radial opening 23 having parallel sides. 24 is a polygonal head engaging the radial opening and 25 is a shank integral with the head extending through the eccentric 25 and externally threaded beyond the eccentric to receive the nut 2lvfor clamping the head to the eccentric. The shank is also formed beyond the nut with the diametral slot 28 for receiving a lsuitable tool, such as a screw driver, to position the head 24 so that its major axis extends radially of the brake. The length `of the radial opening is greater than the length of the head 24 to provide radial clearance per-1 mitting radial movement of the trailing end portion of the shoe. The eccentric 26 extends through and is mounted on the backing plate I3, the eccentric having the enlargement 29 which is adaptedL to be clamped against the backing plate by the nut 39 threaded upon the eccentric.

With this construction, it will be seen that each of the eccentrics 25 can be rotatably adjusted upon the backing plate I3 after the nuts 30 have been loosened. Also that the heads 24 can be rotatably adjusted after the nuts 2l have been loosened to radially position the major axes of the heads. By adjusting the anchors for the lower and upper left shoes and l, respectively, the disc and also the shoes may be bodily moved to center the same with respect to the brake drum.

The shoes are moved radially outwardly against the internal friction face of the brakedrum by flattening the resilient dished disc andthereby ,Y

compelling the radially outer ends of the disc spokes to move radially outwardly. The mechanism for flattening the disc comprises the axially extending tubular member 3| which extends through the central portion 9 of the disc and has the radial flange 32 for abutting the outboard side of the central portion to operatively connect the tubular member to the disc. The mechanism also comprises the axially extending rotatable ring 33 telescoping the tubular member 3l with the telescoping portions of the tubular member and ring formed with the opposite annular grooves 34 and 35, respectively, in their adjacent faces. 33 is a transversely split resilient wire extending within the grooves for operatively connecting the ring to the tubular member and at the same time permitting relative rotation thereof.` 'I'he wire is insertable through a slot 3l in the telescoping portion of Athe ring and the wire preferably has at one end the transverse terminal portion 38 which extends radially. outwardly beyond the telescoping portion of the ring.

For the purpose of compellingl the ring 33 to move axially in an lnboard direction and toward the backing plate I 3 upon rotation of the ring in one direction, the inboard end of the ring is formed with the cams 39 which are preferably arranged in pairs equally'spaced about the periphery of the ring. The backing plate has secured thereto the brackets 4U, each of which is provided with the stationary cams lli arranged for engagement by the cams 33. The cams 39 and 4I are inclined toward the backing plate I3 in a direction such that when the ring is rotated in the direction of the arrow, shown in Figure 6, the ring is compelled to move axially toward the backing plate to correspondingly move .the tubular member and thereby flatten the disc. The brackets lil are adjustably secured to the backing plate by means of the studs 42 and the nuts d3, the studs extending through enlarged holes in the brackets. To rotate the ring 33 in the direction of the arrow shown in Figure 6, IY have xedly mounted upon the telescoping portion of the ring the bracket 14. This bracket extends generally radially from the ring and is operatively connected to the fluid pressure operated actuator or wheel cylinder i5 which is located adjacent the ring. The actuator comprises the cylinder 3S which extends chordw'ise of the drum closely adjacent to the ring 33 and is xedly secured to the backing plate I3 by suitable means, such as the bolt 3l. 48 is a piston slidable within the cylinder and operatively connected to the piston rod 49, which in turn is operatively connected to the bracket 44.

To normally hold the ring 33 in its retracted position, at which time the disc 8 is in its normal position and the shoes are retracted, I have provided the coil spring 50 having one end connected to the bracket 44 and the other end connected to the lug 5I upon the cylinder 66. 52 is a screw threaded through the lug 5I and abutting the bracket 44 to locate the ring 33 in its normal position.

In operation and with the parts in their normal retracted positions, it will be seen that when braking fluid under pressure is forced into the cylinder 6 it acts upon the piston i8 which, in turn, acts through the piston rod 39 upon the bracket M to rotate the ring 33 in the direction of the arrow shown in Figure l and also in the direction of the arrow shown in Figure 6. The rotation of the ring compels the cams 39 to ride over theY cams 4I which cooperate to move the ring 33 axially in an inboard direction toward the backing plate I3. As a result, the tubular member V3| is compelled to correspondingly axially move and the disc 8 is attened and the ends of its spokes force the shoes 5, E and 'I against the brake drum. Upon relieving the fluid pressure, it will be seen that the retracting spring 5) returns the parts to their normal positions, at which time the bracket ad abuts the screw 52.

From the above description, it will be readily seen that I have provided a powerful mechanism for flattening the disc. Also that the fluid pressure operated actuator or wheel cylinder is located closely adjacent the ring of the mechanism and mounted on the inner portion of the backing plate so that the latter may easily resist the stress to which it is subject when the brake is applied.

What I claim as my invention is:

l. In a brake, the combination with a backing plate, a brake drum, internal brake shoes, and a resilient disc for moving said shoes against said drum, said disc having an axially movable central portion and a radially movable outer portion, of mechanism for axially moving' said central portion comprising an axially extending tubular member operatively connected to said central portion, an axially extending rotatable ring operatively connected to said tubular member and formed with cam means, stationary cam means on said backing plate cooperating with said iirst mentioned cam means to axially move said ring upon rotation thereof, a bracket secured to and extending generally radially from said ring, and

a fluid pressure actuated device mounted on said backing plate and extending generally chordwise of the brake adjacent to said ring and having a piston operatively connected to said bracket and movable in a direction to rotate said ring.

2. In a brake, the combination with a backing plate, a brake drum, internal brake shoes, and means for moving said shoes against said drum, said means comprising a member having an axially movable central portion and a radially movable outer portion, of mechanism for axially moving said central portion comprising an axially extending tubular member operatively connected to said central portion, an axially ext-ending rotatable ring, said tubular member and ring having telescoping portions formed with opposed annular grooves in their adjacent faces, a member extending within said grooves for operatively connecting said ring to said tubular member, and cooperating means on said backing plate and ring for axially moving said ring upon rotation thereof.

3. In a-brake, the combination with a backing plate, a brake drum, internal brake shoes, and

means for moving said shoes against said drum, said means comprising a member having an axially movable central portion and a radially movable outer portion, of mechanism for axially moving said central portion comprising an axially extending tubular member operatively connected to said central portion, an axially extending rotatable ring, said tubular member and ring having telescoping portions formed with opposed annular grooves in their adjacent faces, a member extending within said grooves for operatively connecting said ring to said tubular member, and means mounted on said backing plate for axially moving said ring. l

4. In a brake, the combination with a backing plate, a brake drum, internal brake shoes and a resilient dished disc for moving said shoes against said drum, said disc having an axially movable central portion and a radially movable outer portion, of mechanism for axially moving said central portion comprising a rotatable member operatively connected to said central portion, cooperating means on said backing plate and rotatable member for axially moving said rotatable member upon rotation thereof, and a fluid pressure actuated device mounted on said backing plate and extending generally chordwise of the brake adjacent to said rotatable member and having a piston operatively connected to said rotatable member and movable in a direction to rotate the same.

y, PHELPS M- FREER 

